* The slideup panel is only displayed when something is
playing. It starts collapsed showing the media poster
and title of what is currently playing.
* Media controls implemented are volume, progress, shuffle,
repeat and play/pause for all items. Next and previous are only
available when a music item is playing.
* In collapsed mode the panel will display the mute button only
if Kodi is muted. The mute button in expanded mode is always
visible.
* Panel is enabled by default. Users can disable the panel
in Settings
* Implemented listening to Player.OnPropertyChanged notifications
to update shuffle and repeat button states.
Tweaked the Now Playing and Playlist screens to better support YouTube videos
Changed HostConnectionObserver to notify clients not only when the id of what's playing changes but also when the label changes (YouTube videos and pictures for instance don't have ids, so the remote wasn't getting notified of a change in what's playing)